# Tag Info

## Hot answers tagged gas

14

It's important to remember that these pipelines don't exist as a single isolated line and will have a number of branches that tie into the main pipeline and split off for gas to be sold to different locations. This touches on a very broad subject of flow assurance and pipeline network modeling. The pipeline will also be broken into smaller sections by ...

10

is it possible to increase the heat output of the burner by connecting two low-pressure supplies in parallel via a T-piece like this one? The primary factor is gas pressure at the tee. If the gas pressure drop from the low pressure regulator to the tee is negligible and the first tank & low pressure regulator is able to supply enough gas to ...

9

No, connecting two tanks together will not double the flow. The regulators fitted to tanks limit the pressure and flow rate so all you do is double the amount of gas the burner has available ie doubles the time of use. Do NOT interfere with the regulators. There are automatic change over systems that have both tanks connected and it switches over when one ...

8

From my brief involvement in shocks, I think the most likely solution would be to image the exhaust, probably optically, but maybe using interferometry or something depending on what the exhaust is. The most obvious indication that you have supersonic flow is if you can see a shock diamond. I think you could probably also work it out from the length of the ...

7

Lighters usually use Butane. Gas bottles use some or all Propane. Propane pressures are MUCH higher. A plastic 'tank' filled with Propane would probably explode. As size increases the container strength must be increased disproportionately. As temperatures increase pressures rise FAR faster than changes in absolute temperature. We understand from ...

6

Seriously?! :D There are going to be two parts to the solution you are looking for, A) Till the steak is in the cannon B) The steak leaves the cannon, is into the air and cooking starts A) Internal ballistics: You are dealing with compressible flow. NEVER use simple Bernaulli's equation beyond Mach no. 0.3. Make sure you are using correction terms till ...

5

The barometric height formula is defined as: $$p(z) = p(0)\exp(-Mgz/(RT))$$ For a centrifuge the upper expression is transformed to: $$p(r) = p(0)\exp(M\omega^2r^2/(2RT))$$ As you see the $g$ is transformed to the radial acceleration $a = \omega^2 r$. The factor $2$ stems from the integration which you have to do during the derivation of the barometric ...

5

The work is surely path dependent; you can estimate a fast passable value in two way. Isothermal, as in the case when several stages with intercoolers are used (SI Units) KWiso = 2.78*10^-4 * (VolFlowRate) * P1 * LN( P2/P1 ) And Adiabatic with costant ratio of specific heats (k) (SI Units) KWad = 2.78*10^-4 * k /( k-1 ) * (VolFlowRate) * P1 * [(P2 / P1)^(...

5

The short answer is that they don't. Choking is not a bad thing. For a gas flow regulator, it's actually a good thing, because under choking conditions, the mass-flow rate is no longer dependent on the downstream pressure. The mass-flow rate is still dependent on the upstream pressure and the size of the aperture connecting the high and low-pressure sides. ...

5

Steel is routinely used for high pressure storage of industrial argon. For practical purposes it is certainly 'gas tight' although there may be a certain amount of atomic level diffusion into the material in the long term but this is more about contamination than actual leakage. As mentioned in comments the quality of mechanical and welded joints is also ...

5

In the molecular flow region of pressure, the thermal conductivity of an ideal, monatomic gas is obtained by this equation. $$k = \frac{1}{\pi^{3/2} d^2}\sqrt{k_B^3T/m}$$ where $d$ is the collision or molecular diameter and m is the molar mass divided by Avogadro's number. It is independent of pressure. Approximations have been derived for non-monatomic ...

5

I doubt there would be a problem. That type of gauge has a bourdon tube inside that has a curved flattened tube. The tube goes from flat to round as the pressure increases which straightens out the curve and moves the needle. If you subject it to negative pressure, the tube will flatten out more and pull the needle towards the peg. The lowest vacuum you ...

4

In my admittedly limited experience working with plumbers, natural gas pipes are typically made from galvanized steel for interior work, or from black steel pipe for underground. Last-leg fittings and tubes which connect the stub-outs to various appliances are sometimes made from copper and brass. Other materials are possible, as noted here. Some things to ...

4

For question 1, as far as I recall, fiscal metering of long hydrocarbon gas pipelines is done with coriolis effect mass flow meters. To calculate Mach number, all that would be required is the mass flow and the temperature from a thermocouple (along with some estimate of the mixture's heat capacity ratio.) This answer needs checking against reliable ...

4

Depending on fuel, a flame has a certain propagation speed - the speed with which the flame wanders through the medium. If the fuel - oxygen mixture moves faster through the pipe than the propagation speed of the flame, the flame can't 'walk'back. Like trying to run on a threadmill that's to fast. The speed of the fuel-air mixture depends on the area of the ...

4

If there were a crack in the glass, then the pressure difference would first cause air to flow into the lamp, which would cause it to stop working (both the mercury and the low pressure are necessary). If there were a way for mercury to escape from the lamp while it still worked, it would most likely be at the glass-to-metal seal around the filament/...

3

The manufacturer says this about maintanence: annual testing of the non-return valve, body leak tightness and flow capacity is recommended WITT is happy to supply special test equipment Flashback Arrestors are only to be serviced by the manufacturer; the dirt filter may be replaced by competent staff Given that you inherit this equipment ...

3

You can't use the ideal gas law in an open system, but you can use Bernoulli's equation. Starting with the conservation of energy: $$E_{in} = E_{out}$$ We have one source in and two sources out: $$E_{in} = E_{out} + E_{leak}$$ The energy is the sum of the enthalpy and kinetic energy (since the pipe is horizontal): $$(h_1 + v_1^2/2)*m_1 = (h_2 + ... 3 That is a really nice thought experiment! In general I would argue that you only need to know: Total-Pressure ( p_t of your supply) Static/Ambient Pressure ( p_\inftyinto which you are expanding) Taking into account the uncertainties (or tolerances) you will know whether your flow will have reached M=1 in the throat (or how likely it is that it has ... 3 1) In an engineering context efficiency has a very specific meaning ie it is the ratio between the energy you put into a system and the useful work that you get out. In itself this doesn't tell you very much about the amount of pollution produced in the process. Fuel economy is a bit different as it considers the overall energy(fuel) use of the car as a ... 3 Assume that high temperature causes no chemical reactions in the contents or between the contents and the can. High temperature will increase the pressure in the can. Assume the can is fully unaffected in its mechanical integrity up to the point that it fails. With all of the above, when you get the can back at room temperature, it will have no change in ... 3 The difference is in the drag coefficient. Typical drag coefficient of the 50's cars have been in the range of 0.38 to 0.42 or so. typical drag coefficient of modern cars even the ones not renowned for their streamlined body is ranging from 0.26 to 0.34. drag is the retarding force exerted on moving bodies by the media they are moving in. it tries to slow ... 3 Gas is odorized ( mercaptans ) which can be detected at a ppb level. The great majority of people notice the smell and take some corrective action. On the otherhand ,whenever you make something fool proof , a bigger fool comes along ; so there are occasional fires caused by gas leaks. Driving a car is a higher risk that having gas in a home or apartment ... 2 The only major difference the alcohol choice will make is the ionization energy. While the ionization energy for Methanol is 10.85 (source), ethanol is 10.62 eV, while Isopropyl is only 10.10 eV. The slight difference will allow for more molecules at the lower potential to be ionized, making for slightly longer trails. However, this shouldn't be a major ... 2 Divide both sides of the equation by time. This allows you to use flow rates, but does not account for friction, so you will have to account for that with your standard hydraulic formulas. 2 It is possible to calculate this under the assumption that all of the energy from the expansion goes into mechanical energy instead of being lost to heat transfer through the walls. In this case the process is called adiabatic, and the work done is given by$$ W = P_0V_0^\gamma\frac{V_f^{1-\gamma}-V_0^{1-\gamma}}{1-\gamma}, $$where$$ \gamma=\frac{C_p}{...

2

Frictional Heat! In simple terms, the pressure drop that is observed is a result of the friction between the moving fluid, and the stationary walls and column packing. This friction reduces the pressure of the fluid, and in turn heats up both the fluid, and the packing. This topic is discussed at length in Moody's treatise on the subject: Moody, L.F. (...

2

The rate of gas leakage depends on the pressure difference, and in your setup it looks like the pressure difference is constantly decreasing as the test is running. This means that the leak rate parameter ($LR$) in your derivation is the average leak rate over the duration of the test. In my experience, leak rate is usually specified as an instantaneous ...

2

I see nothing in your picture to indicate that the circuit breakers need to be explosion proof. They don't appear to be in a zone 0 location, nor would I expect that any explosion proof volume would extend thru the conduit to the circuit breakers. That just doesn't make sense. Also, cars aren't zone 0 rated in the first place, and neither are all kinds of ...

2

$$\frac{\left(\mbox{amount of gas}\right)\left(\mbox{thickness of membrane}\right)} {\left(\mbox{membrane area}\right)\left(\mbox{time}\right)\left(\mbox{differential pressure of gas}\right)}$$ Units of gas permeability constants (source of the formula) Gas Barrier Introduction Introduction to Material Permeability Indexes

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